1. Field of the Invention
The present invention generally relates to an electronic endoscope system, and, in particular, is directed to the development of an electronic endoscope system in which a region of an organ of a human body is indicated during medical examination of the organ using the electronic endoscope system.
2. Description of the Related Art
As is well known, an electronic endoscope system is utilized to medically examine internal organs of a human body, such as, the esophagus, stomach, bronchi, lungs, and so on. In general, the electronic endoscope system includes a scope having a solid-state image sensor provided at a distal end thereof, an image-signal-processing unit to which the scope is detachably coupled, and a TV monitor connected to the image-signal-processing unit.
When the scope is inserted in an internal organ of a human body, the solid-state image sensor optically photographs an endoscope image, and converts the photographed image into a frame of image-pixel signals. The frame of image-pixel signals is repeatedly read from the solid-state image sensor at a given regular time interval, and is fed to the image-signal-processing unit. The image-signal-processing unit produces a video signal on the basis of the frames of image-pixel signals obtained from the solid-state image sensor, and feeds the video signal to the TV monitor. The TV monitor reproduces the endoscope image as a motion picture in accordance with the video signal.
Before the medical examination can be precisely and promptly performed, it is necessary for a doctor to correctly and quickly determine what region of the organ is being reproduced on the TV monitor, i.e., what region of the organ the distal end of the scope has reached. However, the correct and quick determination of the region of the organ reproduced on the TV monitor is very difficult, especially for a novice who manipulates the scope. Also, when a complex organ, such as the bronchi, is examined using the electronic endoscope system, it is difficult for even a skilful doctor to correctly and quickly determine what region of the complex organ is being reproduced on the TV monitor, i.e., what region of the complex organ the distal end of the scope has reached.